This project is designed to develop and demonstrate a facile, cost-effective, and broadly applicable thin-film coating technology for micro/nanoparticles in diagnostic, biotech, and therapeutic uses. This approach requires the preparation and use of amphiphilic block copolymers containing photoactivatable coupling and polymerizing groups in the hydrophobic block and passivating and biomolecule coupling groups in the hydrophilic block. Current commercial microparticles lack the facile provision of surface properties needed for flowing particle and immobilized microsphere arrays for genomic, proteomic and cellomic assay systems; coated nanofibers for cellomic and tissue engineering applications; coated "quantum dots" for self-encoded particle preparation and for disease studies and treatment requiring particle uptake by living cells. In Phase I, new PhotoLink reagents and coating technology will be developed for covalent bonding of self-assembling monolayer film on micro- and nanoparticles for in vitro and in vivo diagnostic uses. A 50% minimum improvement over current commercial microsphere products is expected in the properties of biomolecule immobilization efficiency, stability, and specific activity. This plan presents an innovative combination in amphiphilic block copolymer design of self-assembling monolayer coating with photoactivatable diradical immobilization and crosslinking chemistry, hydrophilic "brush" passivating coating, and biomolecule immobilization and stabilization properties.